(一)
1.—Can't you stay a little longer?
—It's getting late.I really________go now.My daughter is home alone.
解析：句意：——你不能再多呆会儿吗?——很晚了，我必须得走了。我女儿一个人在家。must“必须，必然要，必定会”。
答案：must
2I________(not) have worried before I came to the new school，for my classmates here are very friendly to me.
解析：句意：我来新学校之前本没有必要担心，因为这里我的同学对我非常友好。needn't have done“本没有必要做某事，表示实际上已经做了某事”。
答案：needn't
3.—Sorry，Mum!I failed the job interview again.
—Oh，it's too bad.You________have made full preparations.
解析：根据语境，本句用should have done sth表示“本应该做某事”，暗含对对方的责怪。
答案：should
4. You________feel all the training a waste of time，but I'm a hundred percent sure later you'll be grateful you did it.
解析：句意：你可能觉得所有的训练都是浪费时间，但是我有100%的把握你以后会感激它的。may“(不确定)可能”。
答案：may
5. I've ordered some pizza，so we ________ worry about cooking when we get home tired.
解析：句意：我已经预订了一些比萨饼，所以当我们到家感到累的时候就不必担心做饭的事了。本题考查情态动词。根据句意可知答案为needn't。
答案：needn't
6. It was sad to me that they，so poor themselves，________ bring me food.
解析：句意：让我难过的是，他们自己那么贫穷，竟然还给我带来食物。本题考查情态动词。情态动词should可以表示说话人惊讶的语气，意为“竟然”。
答案：should
7. The door ________ open，no matter how hard she pushed.
解析：句意：不管她怎么用力推，门就是打不开。“won't/wouldn't open”可表示门很难打开。此处open主动形式表示被动意义。本句题干中有“pushed”，故设空处填wouldn't。
答案：wouldn't
(二)
1.—Can I smoke in this hall?
—No，you can't.If you________，please go to the smoking room.
解析：句意：——我能在大厅吸烟吗?——不行，如果你非要吸，请去吸烟室。此题考查情态动词的特殊用法。must在这里意为“非得，偏要”。
答案：must
2.I________thank you too much because without your help I wouldn't have won the first prize.
解析：句意：我都不知道该怎么谢你了。没有你的帮助我不会获得一等奖。can't与too连用，意为：“再……也不为过”。
答案：can't
3.—I'll have to write a report about “Jane Eyre” next week，but I haven't got the book yet.
—Don't worry.You________have it by noon tomorrow.
解析：句意：——我下周要写一篇关于《简·爱》的报告，但我还没有书呢。——别担心。到明天中午你就会拿到了。此题考查情态动词shall的用法。shall与第二、三人称连用，用于陈述句表示说话者给对方的允诺。
答案：shall
4.—It is a mystery and a shock to all who know him that he________have taken his own life in this way.
—What a pity，indeed.
解析：句意：——他竟然用这种方式结束自己的生命，这让所有认识他的人感到费解和震惊。——真可惜。此题考查情态动词should的用法。should表示对某事不能理解，感到意外，意为“竟会，竟然”。
答案：should
5.Nuclear energy________be really dangerous at times even though it's a kind of nice energy in general.
解析：句意：尽管核能在总体上是一种不错的能源，但它有时可能真的会很危险。can用于肯定句可表示客观上的可能性，意为：“有时会，可能会”。
答案：can
6.It is required by law that a driving test________(take) before a man gets a license.
解析：句意：法律规定，一个人在获得驾照之前要先参加驾照考试。It is required that...中，that从句的谓语动词用“should+动词原形”，其中should可以省略;又因为test与take之间是被动关系，故用被动语态，即(should) be taken。
答案：(should) be taken
7.I________(go) through the hard times but for my teacher's generous and timely help.
解析：句意：要不是老师慷慨而及时的帮助，我不可能熬过那段艰难的岁月。根据句意可知设空处为与过去事实相反的虚拟语气，故答案为couldn't have gone。本句中的but for相当于if it hadn't been for...。
答案：couldn't have gone